Batch rename for the §5.1 generic filenames, paired with their prose edits

[mmcky]

This is the dedicated issue that decision D6 in QuantEcon/workspace-lectures#39 promised ("a batch rename across all five §5.1 files gets its own issue") and that the QuantEcon/workspace-lectures#42 validation confirmed had still not been filed after three separate promises. The register entry at #66 (decision 5, "the rename list for generic filenames") carries the same list; this issue is where the work gets planned and tracked.

The published tree is flat, so the key is a bare filename. From .dev/qeld/migration-catalog.md §5.1, the five names and where each now stands:

file	origin	problem	status now
fp.dta	python.myst	two letters	already migrated and published under the generic name (Track B, D6 kept all seven names as-is; no collision today since lectures/ holds no other .dta)
fred_data.csv	advanced	names a source, not a dataset	not yet migrated — rename at migration
test_pwt.csv	programming	"test"	not yet migrated — rename at migration
acs_data_summary.csv	advanced	plausible but claims a whole survey	not yet migrated — rename at migration
data.csv	programming (about_py.md)	referenced but never exists	nothing to rename — the dangling reference is the fix

Two constraints the catalog already records:

• A rename breaks text qeld cannot reach. The catalog's example is mle.md's prose naming mle/fp.dta; every rename must be paired with its prose/{download} edits in the same PR, found by grep rather than by the audit (§5.2 lists 28 prose refs, 11 naming a data file in two places).
• Timing: the catalog wants this pass done before the remaining tracks migrate — that now means before Tracks C and D land their files, so the three unmigrated names arrive under their final names rather than needing a second breaking change.

For fp.dta, renaming now means a breaking URL change and a coordinated repoint wave for one file. The cheap alternative is to fold it into the Phase 4 interim→final cutover (#15), where every consumer URL changes anyway — proposed default, decide here.

[mmcky]

Decision, 2026-08-17 (recording it here since this issue held the open question): the renames are deferred to phase 2. Wave C2 migrates fred_data.csv and acs_data_summary.csv under their current names, and this issue becomes the phase-2 rename review. dataBHS.csv joins the list — the C2 conversion of dataBHS.mat keeps the stem and changes only the extension, precisely so its real rename happens here alongside its wave-mates rather than naming one file well while the others wait.

Supporting fact from the #96 validation: an org-wide Trees sweep (278 of 278 default branches, positive controls fired) found no same-name-different-content collision for either fred_data.csv or acs_data_summary.csv — every org copy of the latter is the same blob — so deferring the renames introduces no ambiguity in the meantime.