roll: pigweed pw_base64, pw_tokenizer: Add TS base64 module and browser fallback

Add TypeScript implementation for pw_base64 providing base64 encoding, decoding, and binary string conversion with browser (atob/btoa) and Node.js (Buffer) fallback support.

Refactor TS detokenizer to use pigweedjs/pw_base64, and add unit tests in pw_base64/ts and pw_tokenizer/ts.

Original-Bug: b/529967981

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/442072
Original-Revision: c7b1a7bd672ba77e2400b06f393d799bec6425ae

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 8d51077f9d5b24..c7b1a7bd672ba7
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8671922567584392993
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia4a2bb3b0377f9c3facad89ba50a851bd61491f1
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/466485

MODULE.bazel

diff --git a/MODULE.bazel b/MODULE.bazel
index 335d7b1..0dbf522 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -41,8 +41,8 @@
 git_override(
     module_name = "pigweed",
     # ROLL: Warning: this is automatically updated by
-    # ROLL: https://cr-buildbucket.appspot.com/build/8671933410075416065
-    commit = "8d51077f9d5b24ec25c2a0f9f68c464bb2da91e9",
+    # ROLL: https://cr-buildbucket.appspot.com/build/8671922567584392993
+    commit = "c7b1a7bd672ba77e2400b06f393d799bec6425ae",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )