Add dev Makefile; format all markdown with prettier

Adds a minimal Makefile wrapping the toolchain the way sneak's other
repos expose it:

- fmt        gofmt -w plus prettier (4-space tabs, proseWrap: always)
- fmt-check  fail if any Go or Markdown file is unformatted
- lint       golangci-lint run ./...
- test       go test ./...
- check      fmt-check + lint + test (the local pre-commit gate)

Running make fmt normalizes the four existing Markdown docs to the
shared prettier style (80-column proseWrap: always, aligned tables) —
a one-time reflow with no content change. The repo remains exempt from
the rest of the policy scaffold (no Dockerfile, CI, or REPO_POLICIES).

MEMORY.md

@@ -1,44 +1,41 @@
 # Project Memory
 
-Working notes for agents on this repo. Read this alongside TODO.md
-(which holds the step queue and workflow) before starting work.
+Working notes for agents on this repo. Read this alongside TODO.md (which holds
+the step queue and workflow) before starting work.
 
 ## Error handling
 
-Panicking on bad/unexpected errors is allowed and preferred over
-threading unlikely error returns through game code — e.g. write-side
-Close/encode failures where continuing would mean corrupt state. The
-game already unwinds C's exit() calls via a gameEnd panic recovered in
-Run. Return errors where a caller genuinely handles them (save-file
-prompts, restore validation). Reserve deliberate `_ =` discards for
-true best-effort paths (scorefile writes, signal-time autosave), always
-with a comment saying why.
+Panicking on bad/unexpected errors is allowed and preferred over threading
+unlikely error returns through game code — e.g. write-side Close/encode failures
+where continuing would mean corrupt state. The game already unwinds C's exit()
+calls via a gameEnd panic recovered in Run. Return errors where a caller
+genuinely handles them (save-file prompts, restore validation). Reserve
+deliberate `_ =` discards for true best-effort paths (scorefile writes,
+signal-time autosave), always with a comment saying why.
 
 ## Linting
 
-The .golangci.yml is the house standard and may only be modified with
-sneak's explicit permission. To disable a linter, ask, explaining what
-the linter does; he approves specific exceptions, which are recorded
-in the config's "Repo-specific exceptions" block with the approval
-date. Approved so far: paralleltest (2026-07-06); testpackage,
-exhaustive, and mnd (2026-07-07). The complexity linters (cyclop,
-gocognit, nestif) are enabled and clean as of refactor step 7
-(2026-07-07): the whole golangci-lint run is 0 issues, so keep it that
-way — decompose new hot spots rather than reaching for a nolint.
-Line-level //nolint with a reason is used sparingly for C-faithfulness
-(e.g. the authentic "missle" message spellings) and provably-safe gosec
-conversions; each needs a justifying comment.
+The .golangci.yml is the house standard and may only be modified with sneak's
+explicit permission. To disable a linter, ask, explaining what the linter does;
+he approves specific exceptions, which are recorded in the config's
+"Repo-specific exceptions" block with the approval date. Approved so far:
+paralleltest (2026-07-06); testpackage, exhaustive, and mnd (2026-07-07). The
+complexity linters (cyclop, gocognit, nestif) are enabled and clean as of
+refactor step 7 (2026-07-07): the whole golangci-lint run is 0 issues, so keep
+it that way — decompose new hot spots rather than reaching for a nolint.
+Line-level //nolint with a reason is used sparingly for C-faithfulness (e.g. the
+authentic "missle" message spellings) and provably-safe gosec conversions; each
+needs a justifying comment.
 
 ## Faithfulness
 
-Behavior must not change during the idiomatic-Go refactor unless a
-TODO step says so. The 80x24 seed-compatible gameplay, message text
-(including original typos), RNG call order, and C quirks (documented
-in tests like TestHoldScrollGreedyMonsterQuirk) are contract. Doc
-comments keep their "(file.c func_name)" breadcrumbs.
+Behavior must not change during the idiomatic-Go refactor unless a TODO step
+says so. The 80x24 seed-compatible gameplay, message text (including original
+typos), RNG call order, and C quirks (documented in tests like
+TestHoldScrollGreedyMonsterQuirk) are contract. Doc comments keep their "(file.c
+func_name)" breadcrumbs.
 
 ## Debugging
 
-Write real, committed test files with t.Logf output and run plain
-`go test -v`; no throwaway scratch scripts. Successful debug probes
-become regression tests.
+Write real, committed test files with t.Logf output and run plain `go test -v`;
+no throwaway scratch scripts. Successful debug probes become regression tests.