feat: SSH dev routing, model registry UX, chat input toolbar, doc sync

Backend / infrastructure:
- cortex/tools/_projects.py (new): shared project alias registry with ssh_host
  for workstation projects (aether_api, aether_frontend, aether_container)
- cortex/tools/git.py: all git tools route to workstation via SSH when ssh_host set
- cortex/tools/aider.py: aider_run SSH-routes to workstation using bash -l -c
- cortex/routers/local_llm.py: POST /api/models/{id}/edit AJAX endpoint — save
  model edits without page reload or tab reset; returns JSON {ok, label, model_name}
- cortex/llm_client.py: remove Gemini CLI and Claude CLI backends; clean up
  fallback chain and process group tracking (continuation of Gemini CLI removal)
- cortex/routers/auth.py: strip Claude/Gemini CLI auth status checks (CLI removed)
- cortex/routers/chat.py: remove legacy claude/gemini backend fields
- cortex/config.py: clean up CLI-related settings
- cortex/main.py: remove CLI lifecycle hooks

UI:
- cortex/static/local_llm.html: model edit forms now save via fetch() + toast;
  stay on Models tab; update row header label in place on success
- cortex/static/index.html: restructure input area to column layout — textarea
  above, compact toolbar below (Chat/Tools/Attach + Send); fixes dead space at
  M/L/XL sizes; context panel "Role" → "Model" section label
- cortex/static/style.css: column input-area layout; #input-toolbar; flex:1 →
  width:100% on textarea (fixes scrollHeight in column flex context); compact
  send/stop button padding
- cortex/static/app.js: add XL (720px) to height cycle; default M (240px)

Docs:
- cortex/static/HELP.md: S/M/L → S/M/L/XL; add Rebuild to distill table; fix
  "Role selector" references (no such UI); fix "your active role" → Chat role;
  fix ⚡ toggle description; Model Registry section cleanup
- documentation/ARCH__BACKENDS.md: reflect CLI removal, current backend state

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/static/index.html

@@ -115,9 +115,9 @@
                 <div id="ctx-schedule"></div>
             </div>
             <div class="ctx-section">
-                <div class="ctx-section-title">Role</div>
+                <div class="ctx-section-title">Model</div>
                 <div class="ctx-row">
-                    <button id="backend-toggle" class="ctx-btn" title="Active role — click to cycle">chat</button>
+                    <button id="backend-toggle" class="ctx-btn" title="Active model — click to cycle chat role slots">chat</button>
                 </div>
                 <div id="backend-model-hint"></div>
             </div>
@@ -167,24 +167,6 @@
     <div id="messages"></div>
 
     <div id="input-area">
-        <!-- Mode select — compact dropdown, opens upward, MRU sorted -->
-        <div id="mode-select">
-            <button id="mode-select-btn" title="Input mode">
-                <span id="mode-icon">💬</span>
-                <span id="mode-label">Chat</span>
-                <span class="mode-arrow">▲</span>
-            </button>
-            <!-- Populated dynamically in MRU order -->
-            <div id="mode-dropdown"></div>
-            <!-- Note visibility sub-toggle — only shown when note mode is active -->
-            <button id="note-vis-btn" title="Toggle note visibility (private / public)">prv</button>
-            <!-- Tools toggle — routes through the orchestrator tool loop when active -->
-            <button id="tools-toggle" title="Tools disabled — click to enable">⚡</button>
-            <!-- Attach file — images (vision) or text/code files -->
-            <button id="attach-btn" title="Attach image or text file">📎</button>
-            <input type="file" id="file-input" style="display:none"
-                   accept="image/png,image/jpeg,image/webp,image/gif,text/plain,text/markdown,.md,.txt,.py,.js,.ts,.jsx,.tsx,.json,.yaml,.yml,.toml,.html,.css,.sh,.csv,.xml,.rs,.go,.java,.c,.cpp,.h,.rb,.php,.swift,.kt,.sql">
-        </div>
         <!-- Attachment preview — shown when a file is pending -->
         <div id="attachment-row" style="display:none">
             <div id="attachment-preview">
@@ -195,7 +177,26 @@
             </div>
         </div>
         <textarea id="input" rows="1" placeholder="Message…" autofocus></textarea>
-        <div id="send-col">
+        <!-- Compact toolbar: mode, tools, attach | spacer | send/stop -->
+        <div id="input-toolbar">
+            <div id="mode-select">
+                <button id="mode-select-btn" title="Input mode">
+                    <span id="mode-icon">💬</span>
+                    <span id="mode-label">Chat</span>
+                    <span class="mode-arrow">▲</span>
+                </button>
+                <!-- Populated dynamically in MRU order -->
+                <div id="mode-dropdown"></div>
+            </div>
+            <!-- Note visibility sub-toggle — only shown when note mode is active -->
+            <button id="note-vis-btn" title="Toggle note visibility (private / public)">prv</button>
+            <!-- Tools toggle — routes through the orchestrator tool loop when active -->
+            <button id="tools-toggle" title="Tools disabled — click to enable">⚡</button>
+            <!-- Attach file — images (vision) or text/code files -->
+            <button id="attach-btn" title="Attach image or text file">📎</button>
+            <input type="file" id="file-input" style="display:none"
+                   accept="image/png,image/jpeg,image/webp,image/gif,text/plain,text/markdown,.md,.txt,.py,.js,.ts,.jsx,.tsx,.json,.yaml,.yml,.toml,.html,.css,.sh,.csv,.xml,.rs,.go,.java,.c,.cpp,.h,.rb,.php,.swift,.kt,.sql">
+            <div style="flex:1"></div>
             <button id="send">Send</button>
             <button id="stop"><svg data-lucide="square" width="14" height="14" class="btn-icon"></svg> Stop</button>
         </div>