docs(readme): cycle is not a milestone

Separate the pipeline-round axis (cycle) from the tracker-container axis
(milestone); note the milestone fieldtest as the closing gate.

README.md

@@ -23,13 +23,19 @@ Eight skills, each with the agents it primarily dispatches:
 | `implement` | Plan exists | code + tests, uncommitted in working tree | Standard iteration path |
 | `audit` | Cycle closing OR baseline drift suspected | drift report + regression report | Mandatory at cycle close |
 | `debug` | Bug observed | RED test in working tree + cause analysis | Mandatory RED-first for any bug |
-| `fieldtest` | Orchestrator-dispatched post-audit, surface-touching cycle | example fixtures + friction spec | Optional |
+| `fieldtest` | Orchestrator-dispatched post-audit | example fixtures + friction spec | Per-cycle optional; milestone fieldtest is the closing gate for a surface-touching milestone |
 | `docwriter` | API surface stable across N cycles | rustdoc / docstring sweep | Optional |
 | `boss` | User types `/boss` | autonomous-orchestrator session — dispatches the other skills until done-state or bounce-back | User-invoked, never auto-dispatched |
 
-Vocabulary is configurable. AILang calls a cycle a *milestone*
-and a sub-cycle an *iteration*; your project may call them
-*release* and *sprint*, or *epic* and *story*, or whatever fits.
+Vocabulary is configurable. A **cycle** is one round in the
+pipeline graph; your project may call it a *release*, an *epic*,
+or whatever fits, and its sub-unit (the default *iteration*) a
+*sprint* or a *story*. A **milestone** is a distinct, higher
+axis — a tracker container (Gitea/GitHub milestone, Linear
+project) that spans potentially many cycles and closes only when
+the work it promised is complete *and* functional (see
+`docs/pipeline.md` § Milestone-close gate). A cycle close is a
+loop step; it is never a milestone close.
 
 ## The two-layer split