chore: scrub dangling references to deleted specs/plans from sources

docs/specs and docs/plans were retired (prior commit); the source/test
comments that cited them ("spec 0050 §4.1", "spec §Testing N", "per spec",
"the spec's ...") now point at nothing. Strip every such pointer while
preserving the technical substance, the design-ledger contract refs
(C1/C11/C20/C34/C12.1/...), and the Gitea issue refs (#41).

Comment/doc edits only across 20 files — no logic change; full workspace
suite green, clippy clean.

crates/aura-cli/src/main.rs

@@ -908,14 +908,14 @@ mod tests {
 
     #[test]
     fn walkforward_report_is_deterministic() {
-        // spec §Testing 10: the built-in WFO render is byte-identical across two
+        // The built-in WFO render is byte-identical across two
         // calls (C1).
         assert_eq!(walkforward_report(), walkforward_report());
     }
 
     #[test]
     fn walkforward_report_has_one_oos_line_per_window_plus_summary() {
-        // spec §Testing 11: N per-window OOS RunReport lines + one summary line.
+        // N per-window OOS RunReport lines + one summary line.
         let out = walkforward_report();
         let lines: Vec<&str> = out.lines().collect();
         assert_eq!(lines.len(), 4); // built-in roll = 3 windows + 1 summary
@@ -1116,7 +1116,7 @@ mod tests {
         );
     }
 
-    /// E2E acceptance (#41 / spec 0019, the worked example): the real MACD strategy
+    /// E2E acceptance (#41, the worked example): the real MACD strategy
     /// blueprint's swept param surface qualifies the three otherwise-indistinguishable
     /// EMA `length` slots by node name to `macd.fast.length` / `macd.slow.length` /
     /// `macd.signal.length` — the named composite boundary visible end-to-end through
@@ -1149,7 +1149,7 @@ mod tests {
     /// C1-deterministic — two runs of the same window are bit-identical JSON.
     ///
     /// Gated like the ingest `streaming_seam` test: skip (early return) when the
-    /// local Pepperstone archive is absent, so the spec never fails on a machine
+    /// local Pepperstone archive is absent, so the test never fails on a machine
     /// without the data. Uses the verified bounded 2006-08 `AAPL.US` window (the
     /// same FROM_MS/TO_MS the ingest seam test drives) so the two-run determinism
     /// check stays fast.

crates/aura-cli/src/render.rs

@@ -88,7 +88,7 @@ mod tests {
     /// deterministic model as the viewer's data source, carries the Graphviz-WASM
     /// bootstrap, and keeps the C4 four-colour palette. Structural, not pixel:
     /// the DOT/SVG are Graphviz-version-dependent and are exercised by hand
-    /// against the prototype (spec Testing strategy).
+    /// against the prototype.
     #[test]
     fn render_html_is_self_contained_and_embeds_the_model() {
         let html = render_html(&sample_blueprint());