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/style.css

@@ -735,35 +735,28 @@
         .message.note-private .note-content { color: #c9a84c; white-space: pre-wrap; }
         .message.note-public  .note-content { color: #4abfb0; white-space: pre-wrap; }
 
-        /* ── Input area — 3-col: [mode-toggle] [textarea] [send-col] ── */
+        /* ── Input area — column: [attachment?] [textarea] [toolbar] ── */
         #input-area {
-            padding: 12px 20px;
+            padding: 10px 20px 12px;
             background: var(--surface);
             border-top: 1px solid var(--border);
             display: flex;
-            flex-direction: row;
-            gap: 10px;
-            align-items: flex-end;
+            flex-direction: column;
+            gap: 6px;
         }
 
-        /* ── Mode select — compact dropdown ─────────────────────────── */
+        /* ── Compact toolbar below the textarea ─────────────────────── */
+        #input-toolbar {
+            display: flex;
+            flex-direction: row;
+            align-items: center;
+            gap: 6px;
+        }
+
+        /* ── Mode select — positioned container for dropdown only ────── */
         #mode-select {
             position: relative;
             flex-shrink: 0;
-            display: flex;
-            flex-direction: column;
-            align-items: stretch;
-            gap: 4px;
-        }
-
-        /* S: collapse to a single row — mode button + compact tools toggle */
-        #mode-select[data-size="s"] {
-            flex-direction: row;
-            align-items: center;
-        }
-        #mode-select[data-size="s"] #tools-toggle {
-            padding: 3px 7px;
-            font-size: 0.75rem;
         }
 
         #mode-select-btn {
@@ -874,8 +867,7 @@
         #attach-btn:hover { color: rgba(255,255,255,0.6); border-color: rgba(255,255,255,0.25); }
 
         #attachment-row {
-            padding: 0.3rem 0.5rem;
-            border-bottom: 1px solid var(--border);
+            padding: 0.2rem 0;
         }
         #attachment-preview {
             display: inline-flex;
@@ -914,7 +906,8 @@
         #attachment-clear:hover { color: var(--text); }
 
         #input {
-            flex: 1;
+            width: 100%;
+            box-sizing: border-box;
             background: var(--bg);
             border: 1px solid var(--border);
             border-radius: 8px;
@@ -936,16 +929,7 @@
         #input.mode-note.public:focus { border-color: rgba(40,170,150,0.85); }
         #input.mode-otr { border-color: rgba(120,80,160,0.4); background: rgba(120,80,160,0.04); }
 
-        /* Send column — right side, stacked */
-        #send-col {
-            display: flex;
-            flex-direction: column;
-            align-items: stretch;
-            gap: 4px;
-            flex-shrink: 0;
-        }
-
-        /* Send button */
+        /* Send button — sits in #input-toolbar row */
         #send {
             display: flex;
             align-items: center;
@@ -955,11 +939,12 @@
             border: 1px solid var(--user-border);
             color: var(--text);
             border-radius: 8px;
-            padding: 10px 14px;
+            padding: 7px 16px;
             cursor: pointer;
             font-size: 0.9rem;
             text-align: center;
             white-space: nowrap;
+            flex-shrink: 0;
             transition: background 0.15s;
         }
 
@@ -977,10 +962,11 @@
             border: 1px solid var(--error-border);
             color: var(--error-text);
             border-radius: 8px;
-            padding: 10px 14px;
+            padding: 7px 14px;
             cursor: pointer;
             font-size: 0.9rem;
             text-align: center;
+            flex-shrink: 0;
             transition: background 0.15s;
         }