Improve imposter tables: (1) Read-only unless writeable_schema=ON

(2) --unsafe-testing no longer required (3) Does not interfere with
PRAGMA integrity_check.

FossilOrigin-Name: a4430d262b3e129d7f00be1661af563907d7b2e98560a9847cd399129f91247b

diff --cc manifest
index 93adce3fee9505d7995561ccf18db1e39c5b6e8f,2c18c1155444eb62225be7f3640012321742763a..96632b87bdcdc9afb84d6fb5615995901bfe1b74
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Diverse\scleanups\sand\sdocs\sin\sthe\sJS\sand\skvvfs\spieces.\sFunctional\schanges:\s(A)\sensure\sthat\sthe\s'i32'\sJS/WASM\sfunc\sarg/result\sconversion\sworks\sproperly\swith\sa\s64-bit-memory\sWASM\sbuild\s(which\swe\sneither\suse\snor\stest\sbut\s[https://webassembly.org/news/2025-09-17-wasm-3.0/\s|\sthe\snewly-ratified\sWASM\s3.0]\sbrings\swithin\spotential\sreach).\s(B)\sFix\ssqlite3_js_posix_create_file()\sto\snot\sdeallocate\sits\sinput\sarray\sif\sthe\sclient\spasses\sin\sraw\smemory\s(the\slibrary\shas\snever\sused\sit\sthat\sway\sbut\sthe\sAPI\spermits\sit).
- D 2025-09-19T17:24:47.155
 -C Improvements\sto\simposter\stables:\s\s(1)\sThey\sare\sread-only\sunless\swritable-schema\nis\senabled.\s\s(2)\sBecause\sthey\sare\snow\sread-only,\sthe\s".imposter"\scommand\nin\sthe\sCLI\sno\slonger\srequires\sthe\s--unsafe-testing\scommand-line\soption.\n(3)\sImposter\stables\sdo\snot\sparticipate\sin\sa\sPRAGMA\sintegrity_check\sand\shence\ndo\snot\scause\sfalse-positive\serrors.\s\sHowever,\syou\scan\sstill\sdo\san\nintegrity_check\son\sthe\sthe\simposter\stable\sitself\sby\snaming\sthe\simposter\ntable\sas\sthe\sargument\sto\sintegrity_check.
 -D 2025-09-19T17:24:12.005
++C Improve\simposter\stables:\s(1)\sRead-only\sunless\swriteable_schema=ON\n(2)\s--unsafe-testing\sno\slonger\srequired\s(3)\sDoes\snot\sinterfere\swith\nPRAGMA\sintegrity_check.
++D 2025-09-19T17:33:29.757
  F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@@ -2175,8 -2175,11 +2175,9 @@@ F tool/version-info.c 3b36468a90faf1bbd
  F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
  F tool/warnings.sh 1ad0169b022b280bcaaf94a7fa231591be96b514230ab5c98fbf15cd7df842dd
  F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
- P 5e5139c2a162562cee0071d03954ebc0b8938da0b045ec3f5eba32dc8e19604d
- R 39374a1a28932b274e07d195dbea9d94
- U stephan
- Z 8c740e2b096da4198cfd5683f58d6ede
 -P 468a11fd415710042b23880772f6c2c7771008208823fe3b554227a9244dbf92
 -R f09c6f119013a99c86219264c1bd3d49
 -T *branch * imposter-tables
 -T *sym-imposter-tables *
 -T -sym-trunk *
++P 79af65a694fbbb3d501fb2ebd835c259ca644e0dafdd71eeb9f0a7c0e9128a1e ad152ddc4bcf6cfe840b9a36ab76a5ec36afdb1dd96eb7697e4b3df1bf63b00d
++R 40cb735bce42a3fc7ea066af39f44a8e
++T +closed ad152ddc4bcf6cfe840b9a36ab76a5ec36afdb1dd96eb7697e4b3df1bf63b00d
+ U drh
 -Z a8fecea68551ccfe826c7588dedc6269
++Z 249a850104d161bbd5ac157b5bff477d
  # Remove this line to create a well-formed Fossil manifest.

diff --cc manifest.uuid
index d078ee8e68ddb36c7568a8acda279d74fdcd080a,7e0eca6a5aebe5d7968cd24ace72a4299b7308cc..afeff93b0e53c770f8f2791e026d54c16389f1a9
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 79af65a694fbbb3d501fb2ebd835c259ca644e0dafdd71eeb9f0a7c0e9128a1e
 -ad152ddc4bcf6cfe840b9a36ab76a5ec36afdb1dd96eb7697e4b3df1bf63b00d
++a4430d262b3e129d7f00be1661af563907d7b2e98560a9847cd399129f91247b