feat(web): file-type icons, onboarding refresh, and LLM stream watchdog (#136)

## Related Issue

None — continuation of the brand-icons line merged in #131 (same author,
internal PR).

## Problem

The remaining work on the `fix/modelsdev-provider-refresh` line had no
PR: nine commits layered on the #131 tip plus uncommitted follow-up
work. It carries the models.dev provider-refresh fix, web UI polish
(thinking block, composer, onboarding/providers), file-type icons for
the transcript, and an LLM stream-idle watchdog.

## What changed

- Cherry-picked the nine branch commits onto current main:
models.dev-sourced provider refresh on the scheduled catalog pass,
thinking-block rework, dynamic-workflow toggle, permission glyph, mono
accent + mascot indicator, brand icons in the bundle, and bundle
rebuilds.
- Added the uncommitted follow-up work: file-type icons (`fileIcons`
library + `material-icon-theme` mapping + generator script),
onboarding/providers panel rework, and a configurable LLM stream-idle
watchdog (`requestIdleTimeoutMs`, default 180s) that aborts stalled
provider streams with a timeout error.
- Changesets cover every user-perceivable change; the release PR will
pick them up next cycle.

## Checklist

- [x] I have read the
[CONTRIBUTING](https://github.com/PyModel/pythinker-code/blob/main/CONTRIBUTING.md)
document.
- [x] I have linked a related issue (internal continuation PR, no
issue).
- [x] I have added tests that prove my feature works.
- [x] Ran `gen-changesets` skill, or this PR needs no changeset.
- [x] Ran `gen-docs` skill, or this PR needs no doc update.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Added manual Dynamic Workflow controls in the composer and mobile
settings.
* Redesigned onboarding and provider settings with improved navigation,
status feedback, and model details.
* Added file-type icons, monochrome accent styling, animated thinking
indicators, and mascot working states.
* Reworked thinking blocks into collapsible inline panels with live
elapsed timers.
* Added automatic model catalog refresh and configurable stream-stall
timeouts.

* **Bug Fixes**
* Fixed missing brand icons and subagent cards remaining stuck in
“Running.”
  * Improved permission and background-task state synchronization.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: elkaix

.changeset/bundled-brand-icons.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Fix missing brand icons in the bundled web UI.

.changeset/llm-stream-idle-watchdog.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Abort LLM requests whose stream stalls and report a timeout.

.changeset/modelsdev-catalog-refresh.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Refresh model lists for providers imported from the models.dev catalog so newly released models appear automatically.

.changeset/subagent-cards-stuck-running.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Fix subagent cards in the web session view staying Running after they finish.

.changeset/web-dynamic-workflow-toggle.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Add a manual dynamic-workflow toggle to the composer and the mobile sheet.

.changeset/web-file-type-icons.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Show file-type icons next to files in the web transcript.

.changeset/web-mono-accent-mascot.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Add a mono accent option and a mascot working indicator to the web UI.

.changeset/web-onboarding-providers-rework.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Rework the web onboarding flow and provider settings screens.

.changeset/web-permission-glyph.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Use the brand fingerprint icon for the manual-permission glyph in the web UI.

.changeset/web-thinking-block-rework.md

@@ -0,0 +1,4 @@
+---
+"@pymodel/pythinker-code": patch
+---
+Rework the thinking block into an inline collapsible with a live timer.