build: consolidate deps into pyproject.toml; drop requirements*.txt

pyproject.toml is now the single source of truth for dependencies.
The two requirements files duplicated what [project] and
[project.optional-dependencies].dev already declared, and in practice
they would have drifted.

Removed:
  - requirements.txt
  - tests/requirements-dev.txt

Updated to use ``pip install -e ".[dev]"``:
  - .github/workflows/tests.yml (CI install step)
  - CONTRIBUTING.md (local dev setup)
  - README.md troubleshooting block
  - tests/EVALS.md (historical run instructions)

CONTRIBUTING.md also now documents the logging module as the
established convention (not a "future commit"), and adds the pre-push
ruff check that CI enforces.

No behavior change.  Tests still pass (58 / 1 skipped).

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

Author: snapsynapse

.github/workflows/tests.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -r requirements.txt -r tests/requirements-dev.txt
+          pip install -e ".[dev]"
 
       - name: Lint (ruff)
         run: |

CONTRIBUTING.md

@@ -4,13 +4,19 @@ Thanks for your interest. A few conventions that keep the repo easy to maintain.
 
 ## Before you open a PR
 
-1. Install dev dependencies and run the test suite locally:
+1. Install in editable mode with dev extras and run the test suite locally:
    ```bash
    python -m venv .venv && source .venv/bin/activate
-   pip install -r requirements.txt -r tests/requirements-dev.txt
+   pip install -e ".[dev]"
    pytest tests/ -v
    ```
-   Expect 30+ passed, 1 skipped (the live smoke test is opt-in via `SUBSTACK2MD_LIVE=1`).
+   Expect 50+ passed, 1 skipped (the live smoke test is opt-in via `SUBSTACK2MD_LIVE=1`).
+
+2. Before pushing, run the linter the way CI does:
+   ```bash
+   ruff check substack2md tests
+   ruff format --check substack2md tests
+   ```
 
 2. If you changed behavior that users see, update `README.md` and `CHANGELOG.md` in the same PR.
 
@@ -27,7 +33,8 @@ Thanks for your interest. A few conventions that keep the repo easy to maintain.
 
 - Follow existing code style. Indent is 4 spaces.
 - Type hints on new function signatures are encouraged but not strictly required yet.
-- Use the `logging` module for user-visible output (future commit). `print()` is fine for CLI-level messages in `main()`.
+- Use the `logging` module for diagnostics. The module-level `log` object in `substack2md._core` is the shared logger; reserve `print()` for boot-time errors that happen before logging is configured.
+- Run `ruff check` and `ruff format` before pushing; CI enforces both.
 - No em dashes in user-facing strings (markdown output, CLI help, README, docs).
 
 ## Tests

README.md

@@ -229,7 +229,7 @@ This is opt-in and requires no additional authentication; the metadata endpoint
 
 ### "Missing modules" error
 ```bash
-pip install -r requirements.txt
+pip install .
 ```
 
 ### URLs not being converted to wikilinks

requirements.txt

@@ -9,7 +9,7 @@ Base: snapsynapse:main
 ```bash
 python -m venv .venv
 source .venv/bin/activate
-pip install -r requirements.txt -r tests/requirements-dev.txt
+pip install -e ".[dev]"
 
 # Fetch PR code into a local checkout
 git remote add drew https://github.com/drewid74/substack2md.git