chore: remove stale docs and sync runtime defaults

[ai-hpc]

Summary

Removes obsolete internal/historical docs and syncs active docs/config defaults with the current Jetson runtime path: genie-ai-runtime + Qwen3 by default, llama.cpp as fallback/dev.

Changes

• Delete stale launch/alpha/diagram-prompt docs that hard-coded old alpha and llama-server workflow details.
• Rewrite getting-started and operations docs around current dev and Jetson bring-up paths.
• Update repo maps/status/subsystem docs to current LLM module files and genie-ai-runtime default.
• Sync config defaults/comments for Qwen3, ggml-small.bin, and push-to-talk wakeword default.

Real Behavior Proof

• I have built and run the affected code locally (or noted why I could not).
• I have verified the change end-to-end on Jetson hardware.
• I have NOT verified on Jetson hardware, and I explain the equivalent verification path or validation gap below.

Tested profile / hardware (check all that apply):

• jetson
• raspberry_pi
• portable_sbc
• laptop
• mac
• CI-only / docs-only
• Not run locally

What I ran

cargo fmt --all
cargo test -p genie-common core_defaults_match_current_jetson_runtime
cargo test -p genie-common config::tests::optional_ai_provider
cargo test -p genie-core --test tool_dispatch_test
cargo clippy -p genie-common -p genie-core --all-targets -- -D warnings
git diff --check
grep -RInE 'llm/client\.rs|llm/retry\.rs|alpha\.[457]|future Jetson-only LLM|default LLM backend expected|points at `llama\.cpp` today|Phi-4-mini Q4_K_M — the current default|today.s default' README.md GETTING_STARTED.md ARCHITECTURE.md CODEBASE.md doc deploy .github tests crates
grep -RInE 'LAUNCH_PREP|alpha5-reflection|workflow/prompt|doc/workflow' . --exclude-dir=.git --exclude-dir=target

What I observed

The new config default regression test passes, optional provider config tests pass, all 18 tool_dispatch_test cases pass, and clippy passes with -D warnings. The stale-reference greps returned no matches. Not Jetson-tested because this PR changes docs, comments, and config defaults; no deployed service was restarted.

Test plan

• Review rendered docs for broken links and stale runtime wording.
• On Jetson, run make deploy ..., setup-jetson.sh --runtime genie-ai-runtime, and genie-restart-all.sh --hard to validate the updated guide.