generate a workflow per component with its own path triggers

[joshua-temple]

Problem / why

GitHub Actions cannot path-filter per matrix leg (on.push.paths is workflow-global), so a
matrix over components would trigger every leg on any component's path change. F4 already emits
one orchestrate file per component; this issue drives each file's on.push.paths from that
component's triggers and gives each its own component-keyed concurrency group and scoped
setup / build / deploy / finalize jobs.

Scope

This PR does:

• Drive each component file's on.push.paths from that component's triggers / paths
  (writeWorkflowTriggers), replacing the global GetAllTriggers collapse for multi-component
  manifests.
• Emit a per-component concurrency group, replicating the proven pattern already used by
  internal/generate/external.go (a per-component key so distinct components never share a
  group).
• Keep single-component output (the default collapse) byte-identical.

This PR does NOT:

• Change promotion workflows (P2 handles per-component promote files).
• Introduce cross-component ordering.

Files / areas touched

• internal/generate/generator.go - per-component writeWorkflowTriggers / writeConcurrency.
• internal/generate/command.go - wire component triggers into the per-component files.

Tests and coverage required

• Generator unit tests: a two-component manifest emits two orchestrate files, each with its own
  on.push.paths and its own concurrency group.
• A test that the single-component output is unchanged.
• actionlint-clean assertion on the generated multi-component workflows.

Acceptance criteria

• One orchestrate workflow file per component, each path-filtered to that component.
• Each component has a distinct concurrency group.
• Single-component output filenames and contents are unchanged and actionlint-clean.

Dependencies

Blocked by V1 and V2.

[joshua-temple]

Implemented and merged via #514 and #516.