ui: Context usage gauge and panel (#25340)

* feat: WIP

* feat: Retire ChatScreenProcessingInfo component, context, and keepStatsVisible settings

* feat: Always-on gauge with active-model /props, conversation stats and live-reactive reading/output/avg

* feat: Add /tokenize endpoint, TokenizeService, FNV-1a and JSON Schema utilities

* feat: Surface enabled-tools token count in context hover card

* refactor(tools): make toolsStore the sole owner of the OpenAI wire format

Previously mcpStore.getToolDefinitionsForLLM() owned the MCP->OpenAI
shape conversion (plus normalizeSchemaProperties). That created two
sources of truth for what gets sent to the LLM, with the
duplication-prone risk of the deduplicated enabled list (which feeds
the token-count cache) drifting from the bytes actually shipped on
chat.

Now:
- mcpStore: pure protocol state + routing. Drop getToolDefinitionsForLLM
  and the inline OpenAIToolDefinition conversion + normalizeSchemaProperties.
  Doc comment adjusted to declare wire-format ownership as belonging
  to toolsStore. Connection lifecycle, health checks, executeTool,
  and the connections/toolsIndex remain.
- toolsStore: owns the wire shape (added earlier this series). mcpEntries()
  inlines the MCP tool conversion; uses normalizeJsonSchema (the JSON
  Schema util extracted in the prior commit) so missing 'type' fields
  are inferred from defaults. mcpTools getter iterates mcpEntries() so
  the Settings UI and the deduplicated enabled list see the same
  definitions. getEnabledToolsForLLM iterates mcpEntries() instead of
  calling mcpStore, so the JSON sent to the LLM is identical to what
  toolsStore.refreshEnabledToolsTokenCount tokenizes.
- agentic: the chat-completion tools field's type was annotated as
  ReturnType<typeof mcpStore.getToolDefinitionsForLLM>, claiming the
  shape was owned by mcpStore. Switch to ReturnType<typeof
  toolsStore.getEnabledToolsForLLM>, the actual source.

Assisted-by: Claude

* feat: UI WIP

* feat: UI WIP

* feat: UI WIP

* feat: Adjust reasoning submenu layout and spacing

* feat: Adjust context usage gauge thresholds and styling

* feat: Split context usage gauge stats into current and cumulative breakdowns

* chore: Format

* refactor: Cleanup

* refactor: Cleanup

* feat: improve token gauge accuracy and display

* refactor: remove MCP recommendation gating and simplify server visibility

* feat: add token audit logging to ChatStore for debugging

* refactor: Simplify context token reading to use server promptTokens directly

* feat: Replace last-known token tracking with live server-derived stats for accurate streaming gauges

* feat: UI Improvements

* feat: Move prompt processing stats to the preceding user message

* feat: Fix context token double-counting and refine gauge layout

* refactor: remove always-show-agentic-turns setting and simplify agentic turn display

* feat: track and display cache tokens in context gauge

* feat: add diagnostic logging for chat completion requests

* refactor: improve token audit console output with fresh/cached breakdown

* fix: invalidate enabled tools token count cache on tool changes

* test: add unit tests for tools store token count invalidation

* refactor: Remove tools token counting infrastructure

* refactor: Update ChatFormContextGauge to use simplified token tracking

* refactor: Update ChatStore to remove tools token counting

* chore: Formatting

* feat: Improve UI text

* feat: simplify context usage derivation and refine gauge labels

* refactor: cleanup logs

* cleaning

* fix: UI

* refactor: Enums

* refactor: Extract context gauge logic into hook and split UI into sub-components

* refactor: Cleanup comments

---------

Co-authored-by: Pascal <admin@serveurperso.com>

tools/ui/src/lib/components/app/chat/index.ts

@@ -241,13 +241,18 @@ export { default as ChatFormActionAddToolsSubmenu } from './ChatForm/ChatFormAct
 export { default as ChatFormActionAddMcpServersSubmenu } from './ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddMcpServersSubmenu.svelte';
 
 /**
- * **ChatFormReasoningToggle** - Thinking toggle button with effort dropdown
+ * Dropdown submenu for selecting reasoning effort level.
  *
- * A toggle button with lightbulb icon that indicates thinking status.
- * Shows the reasoning effort dropdown when clicked.
+ * Shows a "Reasoning" sub-menu item with a lightbulb icon indicating
+ * thinking status, and a nested list of effort levels.
  * Only visible when the current model supports thinking.
  */
-export { default as ChatFormReasoningToggle } from './ChatForm/ChatFormActions/ChatFormReasoningToggle.svelte';
+export { default as ChatFormActionAddReasoningSubmenu } from './ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddReasoningSubmenu.svelte';
+
+/**
+ * Compact context-usage gauge with per-turn and cumulative breakdown in the tooltip.
+ */
+export { default as ChatFormContextGauge } from './ChatForm/ChatFormContextGauge/ChatFormContextGauge.svelte';
 
 /**
  * Hidden file input element for programmatic file selection.
@@ -669,14 +674,6 @@ export { default as ChatScreenDragOverlay } from './ChatScreen/ChatScreenDragOve
  */
 export { default as ChatScreenForm } from './ChatScreen/ChatScreenForm.svelte';
 
-/**
- * Processing info display during generation. Shows real-time statistics:
- * tokens per second, prompt/completion token counts, and elapsed time.
- * Data sourced from slotsService polling during active generation.
- * Only visible when `isCurrentConversationLoading` is true.
- */
-export { default as ChatScreenProcessingInfo } from './ChatScreen/ChatScreenProcessingInfo.svelte';
-
 /**
  * Server error alert displayed when the server is unreachable.
  * Shows the error message with a retry button.