feat: upgrade to qwen3.5, self-hosted Gitea CI, optimize Docker image

Model upgrade:
- qwen2.5:14b → qwen3.5:latest across config, tools, and docs
- Added qwen3.5 to multimodal model registry

Self-hosted Gitea CI:
- .gitea/workflows/tests.yml: lint + test jobs via act_runner
- Unified Dockerfile: pre-baked deps from poetry.lock for fast CI
- sitepackages=true in tox for ~2s dep resolution (was ~40s)
- OLLAMA_URL set to dead port in CI to prevent real LLM calls

Test isolation fixes:
- Smoke test fixture mocks create_timmy (was hitting real Ollama)
- WebSocket sends initial_state before joining broadcast pool (race fix)
- Tests use settings.ollama_model/url instead of hardcoded values
- skip_ci marker for Ollama-dependent tests, excluded in CI tox envs

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

tox.ini

@@ -4,9 +4,12 @@ no_package = true
 
 # ── Base ─────────────────────────────────────────────────────────────────────
 [testenv]
-allowlist_externals = timeout, perl, docker, mkdir, bash, grep
+allowlist_externals = timeout, perl, docker, mkdir, bash, grep, ruff, pytest, mypy, uvicorn
+sitepackages = true
 commands_pre = pip install -e ".[dev]" --quiet
 
+passenv = OLLAMA_URL
+
 setenv =
     TIMMY_TEST_MODE = 1
     TIMMY_DISABLE_CSRF = 1
@@ -84,7 +87,7 @@ commands =
 # ── CI / Coverage ────────────────────────────────────────────────────────────
 
 [testenv:ci]
-description = CI test suite with coverage + JUnit XML (mirrors GitHub Actions)
+description = CI test suite with coverage + JUnit XML (mirrors Gitea Actions)
 commands =
     mkdir -p reports
     pytest tests/ \
@@ -94,7 +97,7 @@ commands =
         --cov-fail-under=73 \
         --junitxml=reports/junit.xml \
         -p no:xdist \
-        -m "not ollama and not docker and not selenium and not external_api"
+        -m "not ollama and not docker and not selenium and not external_api and not skip_ci"
 
 [testenv:coverage]
 description = Full coverage report (terminal + XML)
@@ -121,7 +124,7 @@ commands =
 # ── Pre-push (mirrors CI exactly) ────────────────────────────────────────────
 
 [testenv:pre-push]
-description = Local gate — lint + full CI suite (same as GitHub Actions)
+description = Local gate — lint + full CI suite (same as Gitea Actions)
 deps =
     ruff>=0.8.0
 commands =
@@ -136,7 +139,7 @@ commands =
         --cov-fail-under=73 \
         --junitxml=reports/junit.xml \
         -p no:xdist \
-        -m "not ollama and not docker and not selenium and not external_api"
+        -m "not ollama and not docker and not selenium and not external_api and not skip_ci"
 
 # ── Pre-commit (fast local gate) ────────────────────────────────────────────