feat(agents): add implementation workflow skills

AGENTS.md

@@ -80,3 +80,5 @@ The domain model (Host, Module, Skeleton, Auto-loader, Enable convention, overla
   The tab rename binding must use the produced literal, such as `prefix+<`, rather than `prefix+shift+comma`.
 - Flake-managed Pi extension, prompt, and skill directories may still be written directly for throwaway development or local experiments.
   The risk is that a later Home Manager activation can overwrite or hide those unmanaged files, so finished work must be promoted into the dotfiles module before it counts as deployed.
+- Pi's tool discovery checks `~/.pi/agent/bin` before `PATH`, and downloaded generic Linux binaries there can be unusable on NixOS with the stub-ld error.
+  A copied or patched Pi launcher that only prepends Nix `fd`/`rg` to `PATH` may still break `@` autocomplete unless the local tool path is removed or Pi validates the local binary before using it.

flake.lock

@@ -562,11 +562,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1785555403,
-        "narHash": "sha256-fFNR+/28b38Y90CcdLpLUuy327eYZrFlw6hYrCIBNh0=",
+        "lastModified": 1785600727,
+        "narHash": "sha256-7Bbj3C+1jyf+YXvUiovCa5t/aCk7BodNf4kV4aZ1Hpw=",
         "ref": "refs/heads/main",
-        "rev": "f283646124403bffa6bda73954d8480235f97990",
-        "revCount": 48,
+        "rev": "346413cd7de5e7d03baea09eb935409cfe6eeaa9",
+        "revCount": 49,
         "type": "git",
         "url": "https://git.alexion.dev/alexion/skills"
       },

modules/agents/skills.nix

@@ -13,6 +13,7 @@ let
   # grill interviews the operator relentlessly to resolve a plan before building.
   # design-skill drafts and audits Agent Skills for structural predictability.
   # wayfinder, research, prototype, and slice guide work from exploration through implementation tickets.
+  # implement, test-driven-development, and review guide execution and validation once tickets are ready.
   skills = with inputs.skills.packages.${pkgs.stdenv.hostPlatform.system}; [
     grill
     design-skill
@@ -20,6 +21,9 @@ let
     research
     prototype
     slice
+    implement
+    test-driven-development
+    review
   ];
 in
 {