source volume is incorrect in librarian generate command #1631
Description
According to the container contract for the generate command, the source volume contains a clone of googleapis, however that doesn't seem to be the case when I run the generate command.
Command
go run ./cmd/librarian generate -repo /usr/local/google/home/partheniou/git/google-cloud-python -library=google-cloud-language -api=google/cloud/language/v1
Log
2025/08/06 15:18:43 INFO Cloning repository url=https://github.com/googleapis/googleapis dir=/tmp/librarian-20250806T151843Z/googleapis
Enumerating objects: 144758, done.
Counting objects: 100% (406/406), done.
Compressing objects: 100% (205/205), done.
Total 144758 (delta 257), reused 206 (delta 201), pack-reused 144352 (from 3)
2025/08/06 15:20:01 INFO Opening repository dir=/usr/local/google/home/partheniou/git/google-cloud-python
2025/08/06 15:20:10 INFO Code will be generated dir=/tmp/librarian-20250806T151843Z/output
2025/08/06 15:20:10 INFO Performing generation for library id=google-cloud-language
2025/08/06 15:20:10 INFO === Docker start ===============================================================
2025/08/06 15:20:10 INFO /usr/bin/docker run --rm -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian:/librarian -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian/generator-input:/input -v /tmp/librarian-20250806T151843Z/output:/output -v /usr/local/google/home/partheniou/git/librarian:/source:ro --user 814163:89939 python-librarian-generator:latest generate --librarian=/librarian --input=/input --output=/output --source=/source
2025/08/06 15:20:10 INFO --------------------------------------------------------------------------------
In the above log, it looks like -v /usr/local/google/home/partheniou/git/librarian:/source:ro is wrong. It should be -v /tmp/librarian-20250806T151843Z/googleapis:/source:ro
What I saw
2025/08/06 15:20:10 INFO /usr/bin/docker run --rm -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian:/librarian -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian/generator-input:/input -v /tmp/librarian-20250806T151843Z/output:/output -v /usr/local/google/home/partheniou/git/librarian:/source:ro --user 814163:89939 python-librarian-generator:latest generate --librarian=/librarian --input=/input --output=/output --source=/source
What I expected
2025/08/06 15:20:10 INFO /usr/bin/docker run --rm -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian:/librarian -v /usr/local/google/home/partheniou/git/google-cloud-python/.librarian/generator-input:/input -v /tmp/librarian-20250806T151843Z/output:/output -v -v /tmp/librarian-20250806T151843Z/googleapis:/source:ro --user 814163:89939 python-librarian-generator:latest generate --librarian=/librarian --input=/input --output=/output --source=/source