Land milestone 4 first-run docs and media

Make the X11 user path visible on first contact instead of burying it under config and maintainer detail.

Rewrite the README around the supported quickstart, expected tray and dictation result, install validation, troubleshooting, and linked follow-on docs. Split deep config and developer material into separate docs, add checked-in screenshots plus a short WebM walkthrough, and add a generator so the media assets stay reproducible.

Also fix the CLI discovery gap by letting `aman --help` show the top-level command surface while keeping implicit foreground `run` behavior, and align the settings, help, and about copy with the supported service-plus-diagnostics model.

Validation: `PYTHONPATH=src python3 -m unittest tests.test_aman_cli tests.test_config_ui`; `PYTHONPATH=src python3 -m unittest discover -s tests -p 'test_*.py'`; `python3 -m py_compile src/*.py tests/*.py scripts/generate_docs_media.py`; `PYTHONPATH=src python3 -m aman --help`.

Milestone 4 stays open in the roadmap because `docs/x11-ga/first-run-review-notes.md` still needs a real non-implementer walkthrough.

docs/developer-workflows.md

@@ -0,0 +1,94 @@
+# Developer And Maintainer Workflows
+
+This document keeps build, packaging, development, and benchmarking material
+out of the first-run README path.
+
+## Build and packaging
+
+```bash
+make build
+make package
+make package-portable
+make package-deb
+make package-arch
+make runtime-check
+make release-check
+```
+
+- `make package-portable` builds `dist/aman-x11-linux-<version>.tar.gz` plus
+  its `.sha256` file.
+- `make package-deb` installs Python dependencies while creating the package.
+- For offline Debian packaging, set `AMAN_WHEELHOUSE_DIR` to a directory
+  containing the required wheels.
+
+## Developer setup
+
+`uv` workflow:
+
+```bash
+uv sync --extra x11
+uv run aman run --config ~/.config/aman/config.json
+```
+
+`pip` workflow:
+
+```bash
+make install-local
+aman run --config ~/.config/aman/config.json
+```
+
+## Support and control commands
+
+```bash
+make run
+make run config.example.json
+make doctor
+make self-check
+make runtime-check
+make eval-models
+make sync-default-model
+make check-default-model
+make check
+```
+
+CLI examples:
+
+```bash
+aman doctor --config ~/.config/aman/config.json --json
+aman self-check --config ~/.config/aman/config.json --json
+aman run --config ~/.config/aman/config.json
+aman bench --text "example transcript" --repeat 5 --warmup 1
+aman build-heuristic-dataset --input benchmarks/heuristics_dataset.raw.jsonl --output benchmarks/heuristics_dataset.jsonl --json
+aman eval-models --dataset benchmarks/cleanup_dataset.jsonl --matrix benchmarks/model_matrix.small_first.json --heuristic-dataset benchmarks/heuristics_dataset.jsonl --heuristic-weight 0.25 --json
+aman sync-default-model --check --report benchmarks/results/latest.json --artifacts benchmarks/model_artifacts.json --constants src/constants.py
+aman version
+aman init --config ~/.config/aman/config.json --force
+```
+
+## Benchmarking
+
+```bash
+aman bench --text "draft a short email to Marta confirming lunch" --repeat 10 --warmup 2
+aman bench --text-file ./bench-input.txt --repeat 20 --json
+```
+
+`bench` does not capture audio and never injects text to desktop apps. It runs
+the processing path from input transcript text through
+alignment/editor/fact-guard/vocabulary cleanup and prints timing summaries.
+
+## Model evaluation
+
+```bash
+aman build-heuristic-dataset --input benchmarks/heuristics_dataset.raw.jsonl --output benchmarks/heuristics_dataset.jsonl
+aman eval-models --dataset benchmarks/cleanup_dataset.jsonl --matrix benchmarks/model_matrix.small_first.json --heuristic-dataset benchmarks/heuristics_dataset.jsonl --heuristic-weight 0.25 --output benchmarks/results/latest.json
+aman sync-default-model --report benchmarks/results/latest.json --artifacts benchmarks/model_artifacts.json --constants src/constants.py
+```
+
+- `eval-models` runs a structured model/parameter sweep over a JSONL dataset
+  and outputs latency plus quality metrics.
+- When `--heuristic-dataset` is provided, the report also includes
+  alignment-heuristic quality metrics.
+- `sync-default-model` promotes the report winner to the managed default model
+  constants and can be run in `--check` mode for CI and release gates.
+
+Dataset and artifact details live in [`benchmarks/README.md`](../benchmarks/README.md).