Ortszeit statt UTC

Setzt den OpenSpec-Change phase-3-ortszeit um (21/21 Aufgaben) und zieht
damit die in Phase 3 eingegangene Abweichung zurueck: DATE$, TIME$, TIMER
und NOW rechnen in der Zeitzone des Rechners, TIMER zaehlt ab der lokalen
Mitternacht.

Versatzermittlung
- jiff 0.2.35 als Abhaengigkeit von tb-runtime
- datetime::utc_versatz(zeitpunkt) ist der einzige Aufrufpunkt der
  Bibliothek; die Kalenderrechnung darunter bleibt Eigenimplementierung
  und sieht sie nie -- zwei Kalendermodelle nebeneinander waeren eine
  dauerhafte Fehlerquelle
- Der Versatz gilt je Zeitpunkt, nicht je Programmlauf: ein Programm, das
  ueber eine Zeitumstellung hinweg laeuft, folgt ihr

Zonenzustand
- Zeitzone { System, Fest(i32), Unbekannt } im RtState
- Fest(n) macht Tests und Korpusprogramme unabhaengig von der Zone des
  Testrechners; TZ waere prozessweit und set_var seit Rust 2024 unsafe

Rueckfallebene
- Ohne ermittelbare Zone gilt UTC, das Programm laeuft weiter
- tbc run meldet den Rueckfall einmal beim Start auf der Fehlerausgabe,
  nicht je Abfrage -- ein stiller Wechsel waere ein Verstoss gegen den
  Guiding Principle

Korpus
- Neue Direktive ' tb-tz: +-HH:MM im Harness
- zeitzone.bas prueft Ortszeit, TIMER ab lokaler Mitternacht und den
  Programmversatz gegen eine gesetzte Uhrzeit
- datumzeit.bas auf die Direktive umgestellt; Sollausgabe unveraendert

Nebenbefund
- TIMER trennt jetzt ganze Sekunden (Ortszeit) vom Bruchteil
  (Systemuhr). Ohne die Trennung waere TIMER in Zonen mit halbstuendigem
  Versatz gesprungen.

Dokumentation: die Abweichung "Uhr laeuft in UTC" entfaellt aus
sprachreferenz.md; bibliothek.md und PLAN.md nachgezogen, jiff steht im
Stufe-2-Ideenspeicher neben crossterm.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -14,6 +14,12 @@ version = "1.0.104"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "330a5ed07fa54e4702c9d6c4174f74427fc0ef6e214bbd677ae50a5099946470"
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.13.1"
@@ -61,7 +67,7 @@ version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "829d955a0bb380ef178a640b91779e3987da38c9aea133b20614cfed8cdea9c6"
 dependencies = [
- "bitflags",
+ "bitflags 2.13.1",
  "crossterm_winapi",
  "mio",
  "parking_lot",
@@ -114,6 +120,37 @@ dependencies = [
  "syn 3.0.4",
 ]
 
+[[package]]
+name = "defmt"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2953bfe4f93bbd20cc71198842756f77d161884c99ebbabc41d80231ded88d1"
+dependencies = [
+ "bitflags 1.3.2",
+ "defmt-macros",
+]
+
+[[package]]
+name = "defmt-macros"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bad9c72e7ca2137e0dc3813245a0d282fd6daad32fd800af018306a9169b5fe8"
+dependencies = [
+ "defmt-parser",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
+[[package]]
+name = "defmt-parser"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "10d60334b3b2e7c9d91ef8150abfb6fa4c1c39ebbcf4a81c2e346aad939fee3e"
+dependencies = [
+ "thiserror",
+]
+
 [[package]]
 name = "either"
 version = "1.18.0"
@@ -202,6 +239,59 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
+[[package]]
+name = "jiff"
+version = "0.2.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "668b7183bd07af9a4885f5c35b0cc5c83c4607a913c16b7e17291832910d2dcc"
+dependencies = [
+ "defmt",
+ "jiff-core",
+ "jiff-static",
+ "jiff-tzdb-platform",
+ "log",
+ "portable-atomic",
+ "portable-atomic-util",
+ "serde_core",
+ "windows-link",
+]
+
+[[package]]
+name = "jiff-core"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7feca88439efe53da3754500c1851dedf3cb36c524dd5cf8225cc0794de95d09"
+dependencies = [
+ "defmt",
+]
+
+[[package]]
+name = "jiff-static"
+version = "0.2.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a69dcb3a21cfb32ce1cd056169337ca284af0766dd766e7878819b251a49204"
+dependencies = [
+ "jiff-core",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
+[[package]]
+name = "jiff-tzdb"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "142bd39932ad231f10513df9ab62661fead8719872150b7ad02a2df79f4e141e"
+
+[[package]]
+name = "jiff-tzdb-platform"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "875a5a69ac2bab1a891711cf5eccbec1ce0341ea805560dcd90b7a2e925132e8"
+dependencies = [
+ "jiff-tzdb",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.189"
@@ -279,6 +369,21 @@ version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
+[[package]]
+name = "portable-atomic"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05c8b63e8d9609db387f0324918f81d68fe27748f084ef092fb35954d0539a85"
+
+[[package]]
+name = "portable-atomic-util"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2a106d1259c23fac8e543272398ae0e3c0b8d33c88ed73d0cc71b0f1d902618"
+dependencies = [
+ "portable-atomic",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.107"
@@ -303,7 +408,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eabd94c2f37801c20583fc49dd5cd6b0ba68c716787c2dd6ed18571e1e63117b"
 dependencies = [
- "bitflags",
+ "bitflags 2.13.1",
  "cassowary",
  "compact_str",
  "crossterm",
@@ -324,7 +429,7 @@ version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags",
+ "bitflags 2.13.1",
 ]
 
 [[package]]
@@ -333,7 +438,7 @@ version = "0.38.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
 dependencies = [
- "bitflags",
+ "bitflags 2.13.1",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -358,6 +463,26 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "serde_core"
+version = "1.0.229"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67dca2c9c51e58a4791a4b1ed58308b39c64224d349a935ab5039aa360942a48"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.229"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.4",
+]
+
 [[package]]
 name = "signal-hook"
 version = "0.3.18"
@@ -487,6 +612,7 @@ dependencies = [
 name = "tb-runtime"
 version = "0.1.0"
 dependencies = [
+ "jiff",
  "log",
  "thiserror",
  "unicode-width 0.2.0",