read_meta_inputs() previously only included direct inputs of
meta's root node — so a manager-added 'inputs.mcp-matrix' in
agent-dmatrix's flake.nix never surfaced in the dashboard
panel even though it's a real fetched input that nix can
update.
now: BFS the flake.lock graph from root to depth 2. emits
one MetaInputView per fetched (non-follows) node, names are
slash-paths from root — 'hyperhive', 'agent-coder',
'agent-dmatrix/mcp-matrix', 'hyperhive/nixpkgs', etc. that's
the same syntax 'nix flake update' accepts for transitive
inputs, so the existing POST /meta-update path needs no
nix-side change.
depth limit of 2 keeps the panel readable — deeper transitives
(nixpkgs's own deps etc.) would explode it; bumping a level-2
entry re-fetches its sub-inputs anyway.
POST /meta-update's 'which agents to rebuild' derivation
updated for the slash names: anything under hyperhive/
fans out to all agents (shared base); 'agent-<n>/...' picks
out the agent name from before the first slash.
read_meta_locked_revs (used by the deployed:<sha> chip per
container) split out into its own straight root-input lookup
since the chip only cares about the agent's own input.