fix: point the HUMANS.md counterpart references at the file that exists

Why: three governance documents cited `docs/HUMANS.md`, which has never existed -- the human
practitioner rules live at `docs/wiki/HUMANS.md`. One of the three is
`core/instructions/governance.md`, which is `@`-imported into every session in every project,
so an agent following its "read it when making decisions not covered here" pointer hit a dead
path. That file was self-inconsistent: line 73 already cited the correct path while line 82 did
not.

Implementation notes: five occurrences corrected across three files --
`core/instructions/governance.md:82`, `docs/research/governance_principles/CONTROLS.md:5,101,106`,
and `docs/ai-constitution.md:238`. Text is otherwise untouched; this is a path correction only,
not a change to any governance rule. Marked the defect fixed in SIMPLIFICATION-AUDIT.md, which
recorded it in two places as outstanding.

Impact: no rule, gate or behaviour changes. The deployed copy at
`~/.claude/core/instructions/governance.md` no longer matches the repo and stays stale until
`scripts/install.sh` re-runs; it was byte-identical before this commit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YR2CjVumUbEGWcMikcoXBD

core/instructions/governance.md

@@ -79,4 +79,4 @@ The deterministic enforcement layer — pre-commit hooks, CI gates, scanner conf
 *Derived from AI Constitution v1.1 — May 2026. Update this file when the constitution is updated.*
 *Compatible with: governance.md, CLAUDE.md, .github/copilot-instructions.md, .cursor/rules/*.mdc*
 *One source of truth. Do not copy-paste into tool-specific files — reference this file from thin adapters.*
-*Counterparts: `docs/HUMANS.md` (human practitioner rules) | `docs/research/governance_principles/CONTROLS.md` (deterministic enforcement)*
+*Counterparts: `docs/wiki/HUMANS.md` (human practitioner rules) | `docs/research/governance_principles/CONTROLS.md` (deterministic enforcement)*