feat: implement resource resizing for VMs with storage management

- Added KnownHostsManager to handle cleanup of SSH known_hosts entries upon VM deletion.
- Introduced disk_size_bytes method in ImageStore to read logical disk capacity.
- Enhanced LifecycleService to manage VM resource resizing, including CPU, RAM, and storage.
- Updated application configuration to support known_hosts_files for SSH management.
- Modified dashboard to include resource resizing options in the UI.
- Improved error handling and validation for resource inputs in the dashboard.
- Removed obsolete .pyc files from the repository.

uvm/dashboard/static/index.html

@@ -171,6 +171,16 @@
             <div class="page-heading detail-heading"><div><span class="subtle-label">A closer look</span><h1 id="detail-heading" tabindex="-1"></h1><span id="detail-id" class="mono muted"></span></div><div id="detail-actions" class="button-row"></div></div>
             <div id="detail-error" class="notice notice-error" hidden></div>
             <div class="detail-grid"><article class="soft-panel detail-card"><header class="section-heading"><h2>The essentials</h2><span id="detail-status"></span></header><dl id="detail-config" class="detail-list"></dl></article><article class="soft-panel detail-card"><header class="section-heading"><h2>A place in the network</h2><svg class="icon caption-icon"><use href="#i-network"/></svg></header><dl id="detail-network" class="detail-list"></dl></article></div>
+            <article class="soft-panel resources-panel">
+              <header class="section-heading"><div><h2>Room to grow</h2><span>Adjust CPU, memory, and private storage.</span></div><button id="edit-resources-btn" class="button button-small" type="button" data-action="edit-resources">Resize resources</button></header>
+              <p id="resize-note" class="panel-footnote">Resource changes stop the machine, apply the new size, and start it again with its existing IP and guest credentials.</p>
+              <form id="resize-form" hidden>
+                <div class="form-grid"><label class="field" for="resize-cpu"><span>CPU capacity</span><input id="resize-cpu" type="number" min="0.01" step="any" placeholder="Keep current CPU" /></label><label class="field" for="resize-ram"><span>Memory</span><input id="resize-ram" type="text" placeholder="Keep current memory" /><small>At least 128 MiB. For example, 4G.</small></label></div>
+                <label class="field storage-field" for="resize-storage"><span>Private storage</span><input id="resize-storage" type="text" placeholder="Keep current size (at least 30G)" /><small>Minimum 30 GiB. A smaller disk must still fit the existing filesystem data.</small></label>
+                <p id="resize-error" class="form-error" role="alert"></p>
+                <div class="button-row"><button id="resize-submit" class="button button-primary button-small" type="submit">Resize &amp; restart</button><button class="button button-quiet button-small" type="button" data-action="cancel-resize">Cancel</button></div>
+              </form>
+            </article>
             <article class="soft-panel ssh-panel"><div><span class="round-icon"><svg class="icon"><use href="#i-terminal"/></svg></span><div><h2>A direct connection</h2><p id="ssh-hint" class="muted"></p></div></div><div class="ssh-command"><code id="ssh-command"></code><button class="icon-button" data-action="copy-ssh" type="button" aria-label="Copy SSH command"><svg class="icon"><use href="#i-copy"/></svg></button></div></article>
             <article class="soft-panel ports-panel"><header class="section-heading"><div><h2>Private port policy</h2><span>Just the connections this machine needs.</span></div><div class="button-row"><button id="edit-ports-btn" class="button button-small" type="button" data-action="edit-ports">Edit rules</button><button id="sync-ports-btn" class="icon-button" type="button" data-action="sync-ports" aria-label="Sync port policy" title="Sync port policy"><svg class="icon"><use href="#i-refresh"/></svg></button></div></header><div id="detail-ports" class="port-list"></div><form id="port-editor" class="port-editor" hidden><label class="field" for="port-input"><span>Port rules <small>PORT:TCP, PORT:HTTP, or PORT:HTTPS</small></span><input id="port-input" type="text" placeholder="22:TCP, 80:HTTP, 443:HTTPS" spellcheck="false" /></label><p id="port-error" class="form-error" role="alert"></p><div class="button-row"><button class="button button-primary button-small" type="submit" value="set">Replace rules</button><button id="open-ports-btn" class="button button-small" type="submit" value="open">Open ports</button><button id="close-ports-btn" class="button button-small" type="submit" value="close">Close ports</button><button class="button button-quiet button-small" type="button" data-action="cancel-ports">Cancel</button></div><p class="panel-footnote">An empty replacement creates a managed policy with no inbound TCP ports.</p></form></article>
             <article class="soft-panel log-panel"><header class="section-heading"><div><h2>A window into the runtime</h2><span>Recent Firecracker log entries.</span></div><div class="button-row"><label class="select-wrap"><span class="sr-only">Log tail length</span><select id="log-tail"><option value="100">100 lines</option><option value="250">250 lines</option><option value="500">500 lines</option><option value="1000">1,000 lines</option></select></label><button id="log-refresh-btn" class="icon-button" type="button" data-action="refresh-logs" aria-label="Refresh logs"><svg class="icon"><use href="#i-refresh"/></svg></button></div></header><pre id="log-output" class="log-output" tabindex="0"></pre><p id="log-meta" class="panel-footnote"></p></article>
@@ -182,6 +192,7 @@
           <div class="page-heading"><div><span class="subtle-label">Every idea starts somewhere</span><h1 id="create-heading" tabindex="-1">Make something new<span class="heading-period">.</span></h1></div><a class="quiet-link" href="#vms">Back to machines <svg class="icon"><use href="#i-arrow"/></svg></a></div>
           <form id="create-form" class="create-layout">
             <div class="create-fields"><section class="soft-panel form-section"><header class="section-heading"><div><h2><span class="step-number">01</span>A name and a little space</h2><span>Give your new machine a shape.</span></div></header><label class="field" for="create-name"><span>Machine name <small>Optional</small></span><input id="create-name" type="text" name="name" placeholder="e.g. my-little-server" pattern="[a-z][a-z0-9\-]{0,62}" maxlength="63" autocomplete="off" /></label><fieldset class="preset-fieldset"><legend>Start with a size</legend><div class="size-presets"><button class="size-preset active" type="button" data-preset="small" aria-pressed="true"><svg class="icon"><use href="#i-server"/></svg><strong>Small</strong><span>1 vCPU · 512 MiB</span></button><button class="size-preset" type="button" data-preset="balanced" aria-pressed="false"><svg class="icon"><use href="#i-server"/></svg><strong>Balanced</strong><span>2 vCPU · 1 GiB</span></button><button class="size-preset" type="button" data-preset="roomy" aria-pressed="false"><svg class="icon"><use href="#i-server"/></svg><strong>Roomy</strong><span>4 vCPU · 2 GiB</span></button></div></fieldset><div class="form-grid"><label class="field" for="create-cpu"><span>CPU capacity</span><input id="create-cpu" name="cpu" type="number" value="1" min="0.01" step="any" required /><small>Fractional requests round up to whole vCPUs.</small></label><label class="field" for="create-ram"><span>Memory</span><input id="create-ram" name="ram" type="text" value="512M" required /><small>At least 128 MiB. Try 512M, 1G, or 2G.</small></label></div></section>
+            <section class="soft-panel form-section"><label class="field" for="create-storage"><span>Private storage</span><input id="create-storage" name="storage" type="text" value="30G" required /><small>Minimum 30 GiB. Try 30G, 50G, or 1T. You can resize this disk later.</small></label></section>
             <section class="soft-panel form-section"><header class="section-heading"><div><h2><span class="step-number">02</span>A way to connect</h2><span>Private networking and guest access.</span></div></header><label class="field" for="create-guest-ip"><span>Guest IPv4 address <small>Optional</small></span><input id="create-guest-ip" name="guest_ip" type="text" placeholder="Automatically assigned" autocomplete="off" /></label><div class="form-grid"><label class="field" for="create-username"><span>Guest user</span><input id="create-username" name="username" type="text" value="root" autocomplete="username" required /></label><label class="field" for="create-password"><span>Guest password</span><span class="password-field"><input id="create-password" name="password" type="password" value="root" autocomplete="new-password" maxlength="128" required /><button class="icon-button" type="button" data-action="toggle-password" aria-label="Show password" aria-pressed="false"><svg class="icon"><use href="#i-eye"/></svg></button></span></label></div><p class="panel-footnote">Use an account that exists in your guest image. Credentials are applied to the machine’s private disk.</p></section>
             <section class="soft-panel form-section"><header class="section-heading"><div><h2><span class="step-number">03</span>Open the right doors</h2><span>Choose which private TCP services are allowed.</span></div></header><label class="toggle-field"><span><strong>Include the default SSH rule</strong><small>Allow TCP port 22 for terminal access.</small></span><input id="create-default-ssh" name="default_ssh" type="checkbox" checked /><span class="toggle-track" aria-hidden="true"></span></label><label class="field" for="create-ports"><span>Additional port rules <small>Optional</small></span><input id="create-ports" name="ports" type="text" placeholder="80:HTTP, 443:HTTPS" spellcheck="false" /><small>Separate rules with commas. HTTP and HTTPS both use TCP.</small></label></section></div>
             <aside class="create-summary soft-panel"><div class="summary-art" aria-hidden="true"><div></div><div></div><span><svg class="icon"><use href="#i-server"/></svg></span></div><span class="subtle-label">Your next little machine</span><h2 id="create-summary-name">Room for an idea.</h2><p>A private disk, a network identity,<br />and a fresh start.</p><dl id="create-summary-details" class="detail-list"></dl><p id="create-error" class="form-error" role="alert"></p><button id="create-submit" class="button button-primary button-wide" type="submit"><span>Create machine</span><svg class="icon"><use href="#i-arrow"/></svg></button><a href="#vms" class="quiet-link summary-cancel">Maybe later</a><span class="summary-note"><svg class="icon"><use href="#i-spark"/></svg>Built on Firecracker</span></aside>