docs: update CI/CD references from GitLab to Gitea

Replace .gitlab/.gitlab-ci.yml with .gitea/workflows/ci.yaml, update
CI_JOB_TOKEN → github.token, CI_PIPELINE_IID → github.run_number, and
update setup instructions to point to git.padelnomics.io deploy keys.

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

CLAUDE.md

@@ -118,11 +118,11 @@ uv add --package new_source extract-core niquests
 - Each tick: git pull (tag-based) → due extractors → SQLMesh → export_serving → web deploy if changed
 - Crash-safe: systemd `Restart=always` + 10-minute backoff on tick failure
 
-**CI/CD** (`.gitlab/.gitlab-ci.yml`) — pull-based, no SSH:
-- `test` stage: pytest, sqlmesh test, web pytest
-- `tag` stage: creates `v${CI_PIPELINE_IID}` tag after tests pass (master branch only)
+**CI/CD** (`.gitea/workflows/ci.yaml`) — pull-based, no SSH:
+- `test-cli`, `test-sqlmesh`, `test-web` jobs: pytest, sqlmesh test, web pytest
+- `tag` job: creates `v${github.run_number}` tag after all tests pass (master branch only)
 - Supervisor polls for new tags every 60s, checks out latest, runs `uv sync`
-- No SSH keys or deploy credentials in CI — only `CI_JOB_TOKEN` (built-in)
+- No SSH keys or deploy credentials in CI — only `github.token` (built-in Gitea Actions)
 
 **CLI modules** (`src/materia/`):
 - `cli.py` — Typer app with subcommands: pipeline, secrets, version